Smolensky District, Smolensk Oblast in the context of Dukhovshchinsky District

The Kasplya (Belarusian and Russian: Каспля) is a river in Smolensky, Demidovsky, and Rudnyansky Districts of Smolensk Oblast of Russia and in Vitebsk Region of northern Belarus. It is a major left-bank tributary of the Daugava. Of its total length of 136 kilometres (85 mi), the first 116 kilometres (72 mi) are in Russia, and the rest in Belarus. It joins the Daugava in the urban-type settlement of Surazh. The town of Demidov is situated on the Kasplya.

The Kasplya originates from Lake Kasplya in Smolensky District. It flows north, crosses the border with Demidovsky District and turns northwest. It flows through Demidov, and next to the selo of Boroda turns west, crosses Rudnyansky District and enters Belarus. There, it turns northwest again and enters the Daugava.

Katyn (Russian: Кáтынь [ˈkatɨnʲ]; Polish: Katyń [ˈkatɨɲ]) is a rural locality (a selo) in Smolensky District of Smolensk Oblast, Russia, located approximately 20 kilometers (12 mi) to the west of Smolensk, the administrative center of the oblast. The village had a population of 1,737 in 2007.

Gnezdovo or Gnyozdovo (Russian: Гнёздово) is an archeological site located near the village of Gnyozdovo in Smolensky District, Smolensk Oblast, Russia. The site contains extensive remains of a Slavic-Varangian settlement that flourished in the 10th century as a major trade station on the trade route from the Varangians to the Greeks.

Demidovsky District (Russian: Деми́довский райо́н) is an administrative and municipal district (raion), one of the twenty-five in Smolensk Oblast, Russia. It is located in the northwest of the oblast and borders with Zharkovsky District of Tver Oblast in the north, Velizhsky District in the northwest, Rudnyansky District in the southwest, Smolensky District in the south, and with Dukhovshchinsky District in the east. The area of the district is 2,514.02 square kilometers (970.67 sq mi). Its administrative center is the town of Demidov. Population: 14,039 (2010 Census); 18,167 (2002 census); 24,237 (1989 Soviet census). The population of Demidov accounts for 52.2% of the district's total population.

Rudnyansky District (Russian: Рудня́нский райо́н) is an administrative and municipal district (raion), one of the twenty-five in Smolensk Oblast, Russia. It is located in the west and northwest of the oblast and borders with Velizhsky District in the north, Demidovsky District in the northeast, Smolensky District in the east, Krasnensky District in the south, and with Vitebsk, Liozna, and Dubrowna Districts of Vitebsk Region of Belarus in the west. The area of the district is 2,111.41 square kilometers (815.22 sq mi). Its administrative center is the town of Rudnya. Population: 25,244 (2010 Census); 28,037 (2002 census); 34,724 (1989 Soviet census). The population of Rudnya accounts for 39.7% of the district's total population.

Gnyozdovo (Russian: Гнёздово) is a village in Smolensky District, Smolensk Oblast, Russia, located on the right bank of the Dnieper River twelve kilometers downstream from Smolensk, in the proximity of Katyn. The village is noted for its extensive remains of a Slavic-Varangian settlement which flourished in the 10th century as a major trade station on the trade route from the Varangians to the Greeks, see Gnezdovo for details.54°47′10″N 31°50′20″E / 54.7861111211°N 31.8388888989°E / 54.7861111211; 31.8388888989